Morning Gents,

I have an Octavia RS on a Y Plate, this car has done 106k miles.

The car doesn't idle very well, when I start it up it hunts at idle and when driven it clears away ok.

However the car had been sitting for a week and the battery went flat, so jump started it off my diesel car and took it out for a ten min drive and it cut out at idle everytime.

Now it's back at home and when I start it, the car hunts at idle until I rev it and then after about 2 mins idles fine.

Any ideas guys?

Thanks!

Morning Gents,

I have an Octavia RS on a Y Plate, this car has done 106k miles.

The car doesn't idle very well, when I start it up it hunts at idle and when driven it clears away ok.

However the car had been sitting for a week and the battery went flat, so jump started it off my diesel car and took it out for a ten min drive and it cut out at idle everytime.

Now it's back at home and when I start it, the car hunts at idle until I rev it and then after about 2 mins idles fine.

Any ideas guys?

Thanks!

Try and unplug MAF and see how it runs??? Could also be a bad coil pack???

Coolant temp sensor maybe at fault. Very common problem & easy to replace, buy a genuine VAG one though. £16ish from GSF or Trade Part Specialists.

I'll try the MAF now, the EML light isn't on so can't check any codes.

Cars runs at normal op temp and gets there fairly quick so don't think its that.

Coolant temp sensor maybe at fault. Very common problem & easy to replace, buy a genuine VAG one though. £16ish from GSF or Trade Part Specialists.

Ahh... you may have just solved a problem with my VW Polo!

It's not been idling well for a while and when I start the car in the mornings the coolant light flashes but doesn't come again on if I turn the engine off/on after driving for a while.

Do you think replacing the coolant temperature sensor would help?

Thanks

p.s. Sorry for hijacking your thread.

I would try a throttle body clean before anything else, nice cheap thing to do before rpelacing other parts.

I recently had a similar problem on my '02 reg 96k miles Octavia with a hunting idle and car almost stalling intermittantly, the engine light wasn't on but i had 2 fault codes 17705 and another similar 17*** code. Took the throttle body off and it was filthy, gave it a good clean with carb cleaner and microfibre cloths and a new gasket for £2

Fingers crossed i haven't had any prblems again and all fault codes have gone.

Ahh... you may have just solved a problem with my VW Polo!

It's not been idling well for a while and when I start the car in the mornings the coolant light flashes but doesn't come again on if I turn the engine off/on after driving for a while.

Do you think replacing the coolant temperature sensor would help?

If the level indicator (orange) then you need to clear the bubbles from the two prongs in the expansion tank. Just rub then with a bit of wood/old toothbrush.

If the level indicator (orange) then you need to clear the bubbles from the two prongs in the expansion tank. Just rub then with a bit of wood/old toothbrush.

Thanks - It's a red light thats flashing, but I'll try clearing the bubbles and see if it helps.

Would that cause the uneven engine idling or are they unrelated?

I'll try the MAF now, the EML light isn't on so can't check any codes.

The lack of the EML doesnt mean the ECU hasn't registered a fault codes. Not all faults put the light on.

I'll try the MAF now, the EML light isn't on so can't check any codes.

Cars runs at normal op temp and gets there fairly quick so don't think its that.

There are many codes that don't cause the EML to come on so just because the EML light isn't on doesn't mean that there aren't any fault codes stored in the ECU.

Coolant temp sensor has 2 outputs, one to the gauge & one to the ECU. It is quite common for the gauge to work normally, but the ECU can still be getting wrong signal which will cause fueling issues.

Cleaning the throttle body is always worth doing.

Edited 12 October, 201015 yr by pauldazzle

Unplugged MAF Sensor and car runs and starts fine, this car is being sold soon - should I buy a cheapy off ebay for £25 or a genuine part for £90?

Thanks

Glad you got it sorted.

Beware of cheap MAF's though!! I bought one from GSF once & my car really didn't like it, jerked & bucked like a rodeo horse. Took it straight back & fitted a geniune VAG part, which cost about £75 (exchange) from TPS

Edited 12 October, 201015 yr by pauldazzle

Ahh... you may have just solved a problem with my VW Polo!

It's not been idling well for a while and when I start the car in the mornings the coolant light flashes but doesn't come again on if I turn the engine off/on after driving for a while.

Do you think replacing the coolant temperature sensor would help?

Thanks

p.s. Sorry for hijacking your thread.

Hi,

Also have Polo which does a similar thing. On cold days, less than 5 degrees coolant light flashes as though low coolant. However, after a bout 5-10 mins of driving then switching on and off the problem disappears. Idles ok though and had same problem for about 5 years. Never tries changing the sensor.

Hi,

Also have Polo which does a similar thing. On cold days, less than 5 degrees coolant light flashes as though low coolant. However, after a bout 5-10 mins of driving then switching on and off the problem disappears. Idles ok though and had same problem for about 5 years. Never tries changing the sensor.

I think I've found the problem - I don't think that the sensor likes the vast quantities of oil in the expansion tank...

Planning a coolant flush (then radweld), and an oil change at the weekend :-)

Fingers crossed

I think I've found the problem - I don't think that the sensor likes the vast quantities of oil in the expansion tank...

Planning a coolant flush (then radweld), and an oil change at the weekend :-)

Fingers crossed

Radweld :thumbdown:

Vast quantities of oil in the expansion tank is not good. Sure you haven't got a blown head gasket?

Vast quantities of oil in the expansion tank is not good. Sure you haven't got a blown head gasket?

Not sure if it's a HG or not, but if I change the coolant and oil it will allow me to see how quickly the oil is building up....not ideal but I'm currently looking for a replacement (hence why I joined on this forum!) so just want to keep it going for now.

Has anyone had any experience with Radweld? (Shop sold me K-Seal, said it was better than Radweld and worked on HGs)

Not sure if it's a HG or not, but if I change the coolant and oil it will allow me to see how quickly the oil is building up....not ideal but I'm currently looking for a replacement (hence why I joined on this forum!) so just want to keep it going for now.

Has anyone had any experience with Radweld? (Shop sold me K-Seal, said it was better than Radweld and worked on HGs)

Don't use it in the car not in a turbo car will block lines up no dude

Radweld is strictly a get you home fix. It's really good at blocking radiators & heater matrix's, & not much else!

Get a dye block test done, most mechanics have a kit, & it doesn't cost much to get done.

Turns out mine had an aftermarket one already fitted, so replaced it for a genuine and car drives ace again!

Thanks guys,.

I think I've found the problem - I don't think that the sensor likes the vast quantities of oil in the expansion tank...

Planning a coolant flush (then radweld), and an oil change at the weekend :-)

Fingers crossed

This could be a faulty oil cooler.